1. Field of the Invention
The present invention relates to an electronic environment sensing instrument and more particularly to an electronic environment sensing instrument having an analog indicator that points to a specific point on a scale corresponding to a sensed environmental parameter such as temperature, humidity or the like.
2. Description of Related Art
Two types of conventional environmental sensing instruments are available in the market and include thermometers, hygrometer, anemometers and the like. One is a mechanical instrument, and the other is an electronic instrument. The mechanical instrument has an analog indicator that indicates the current reading and can drive indicators to mark high and low readings for a given period. The digital instrument provides a precise digital readout of the current reading.
With reference to FIG. 9, a conventional mechanical thermometer has a panel (90), a Borden tube assembly (70) and an indicator set (80).
The panel (90) has a front face (not numbered), a scale (not numbered) a through hole (91) and optional high and low indicators (not shown). The scale is on the front face (not numbered), is printed or etched and is a temperature scale, a relative humidity scale or the like. The high and low indicators are pivotally attached to the front face of the panel (90) and respectively indicate high and low readings on the scale.
The Borden tube assembly (70) has a base (71), a copper C-ring (72) and a transmission shaft (73). The base (71) has a front surface (not numbered) and a pivot hole (711). The hole (711) is defined in the front surface of the base (71). The copper C-ring (72) has a proximal end (not numbered) and a distal end (not numbered), is connected to the base (71) and expands or contracts depending on the temperature. The transmission shaft (73) is connected to distal end of the copper ring (72) and has an L-shaped distal end (731).
The indicator (80) is L-shaped and has a shaft (81), a needle (82) and a connector (83). The shaft (81) is mounted through the through hole (91) in the panel (90), rotatably mounted in the hole (711) in the base (71) and has a distal end (not numbered). The distal end protrudes through the through hole (91) in the panel (90). The needle (82) is connected to the distal end of the shaft (81), pivots the high and low indicators on the front face of the panel (90) and indicates the current temperature on the scale on the panel (90). The connector (83) is attached to the shaft (81) and has a mounting hole (831). The mounting hole (831) rotatably holds the L-shaped distal end (731) of the transmission shaft (73) that rotates the shaft (81) in the pivot hole (711) in the base (71) to indicate the current temperature on the scale on the panel (90) when the copper C-ring (72) expands or contracts.
Because the specific current environmental parameter has to be interpolated from the scale on the panel (90) of the device, electronic instruments were designed to provide a precise digital readout of the current sensed environmental parameter. Even though the electronic instruments provide precise instantaneous readings of the current environmental parameter, the electronic environment sensing instrument cannot provide high and low readings without a significant increase in the electronics or the software.
Therefore, the present invention provides an electronic environment sensing instrument that has an analog indicator to obviate or mitigate the problems with conventional mechanical and electronic environment sensing instruments.